Oscar-nominated actress Saoirse Ronan is tackling a new cinematic challenge in the upcoming Stephenie Meyer adaptation "The Host"—namely, playing two characters inhabiting one body.

The film takes place in an alt-future where the vast majority of our race has been implanted with alien beings known as Souls. Melanie (played by Saoirse) is one of the last remaining humans...until she's not. Invaded by Wanda, Melanie doesn't give up the fight for her body, though, and she and the Soul enter into an uneasy alliance, which includes searching for Melanie's family and love Jared (played by Max Irons).

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For Saoirse, playing the dual role of Melanie/Wanda was an opportunity she relished.

"It was challenging but it was great at the same time because I'm either playing one or I'm playing the other, or I'll switch between the two in one scene. So you'll map that out a bit whenever that happens," she explained of her process.

And though Saoirse characterizes Wanda as the "perfect Soul," from the sounds of it, she'd much rather grab an ice cream cone or, you know, fight off interloping aliens with Melanie.

"I really liked it because for the majority of the shoot, I was playing Wanda, who's—she's a great character to play, but she's a perfect Soul and doesn't really feel any negative emotions," Saoirse said. "So I could go from playing the perfect being to someone who's a real fighter, who's really kinda gutsy, who has a mouth on her, and it was really nice to be able to do that."

(Anyone else OBSESSED with the way Saoirse says, "has a mouth on her?" No, just me?)

Click play on the video above to hear more from Saoirse about Melanie's and Wanda's quirks!

"The Host" hits theaters Friday.

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